Cutter knife



FIG. 1 is a plan view of a cutter knife showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left end view thereof;

FIG. 5 is a right end view thereof; and,

FIG. 6 is a perspective view thereof. 

The ornamental design for a cutter knife, as shown and described. 